Dye brightening agent in diazotype process



3,078,162 DYE BREGHTENHNG AGENT N DIAZQTYPE-PROCESS "EdwardC. Bialczak, Johnson .City, and Walter.J..Weleh, Port Dickinson, N.,Y., .assignors to General Aniline dz Film Corporation, New York, N.Y., a corporation of Delaware p 'No Drawing, Filed Aug. 11 1960, -Se'r. No. 49,180 11 Claims. (Cl. 96--49) The present invention pertains toan improvement of dye brightness in prints obtained from light-sensitive diazotype materials and, more particularly, to the accomplishment of this result by re'siirtto aryl phosphonic acids, aryl phosphinic acids, 'a'ryl "sulfiriic acids or boro phos- *phoric acids, or the soluble salts of the same.

As is known, the diazotype process involves treating a base such as paper or the like, with a sensitizing composition containing a lig'ht seiisitive diazo compound, exposing the treated base through a pattern, and subjecting the exposed material to "development by means of an alkali, in the presence'of an "a'zo dye coupling component capable of reacting with the undestroyed diazo compound to produce azo dyestuft images. This process, which is of rather "general application, usually employs coupling components which yield prints which may be maroon, blue, black or sepia,

. The brightness of the. dye formed byth'is :process is dependeht. upon the environment in which the dye is formed. Dye brightness can be enhanced by coating the sensitizing solution'o'n a precoated base. Precoats such as casein and silica are effective in idye brightening. Brightness can also be enhanced by addition of suitable components to the sensitizing solution such as pigments, certain salts such as zinc chloride and certain organic acids or salts of the same. This invention relates to the additionof the latter. V I

It has been discovered that a substantial improvement in dye brightness may be obtained by precoating a base with a composition containing an aryl phosphinic acid, ar'yl phosphonic acid, boro phosphoric acid or an aryl sulfinic acid, or the soluble salts of the same or byadding the dye brightening agent to the sensitizing solution. An improvement in brightness is noted in formulations which produce blue, black, maroon or sepia dye prints. The dye brightening agent, in addition to irnproving brightness, possesses other advantages. They include the following: v I p (l) Decreases gas fade of the dye. I The term gas fading in the diazotype industry relates generally to the adverse effect of atmospheric :g'ases upon the dye image. For example, certain blue dyes upon exposure to atmos phere will vary anywhere from a blu'e, brown or black image. The presence of, ie, phenyl-phosphinic acid hinders markedly this transformation. I I e (2) Causes a hypsochromatic shift. Many of t'he blue dyes used in this are of a very purplish hue, for example, the dye formed by 2,3-dihydroi y naphthalene-6- sulfonic acid and p-N,N-diethylamino benzene diazonium chloride. In the presence of, Le, phenyl-phosphinic acid, a hypsochromatic shift results, with the dye losing its red character. p

'(3) Improvespac kage life 'of the sensitized material. Generally, aged diazotype material does not give as bright :phosp 3,978,162 Patented Feb. 19, 1963 i r an hosiit bh saa ids. ueh. asr sx y fihs ir ei a ..a hthyk h p oatq a id. an th i .eiamq m. P9- a ns. s di man an n sal st' r lx h pl a i such as phenyl phosphinie aeid, diphenylphosphinic acid,

i istq etl y l .r ea -rh phin s a l4- r-i h phosphinic aeidjl), 4-brorn-phenyl-phosphinic acid '(1),

:1-ethyl phenyl phosphinic acid (4 l -methyl phenylphm qa 'j s. (2;). ne h l-r11ailo at ac lrm y hsnx hosnhia s a i t %h Q P Y I h nic acid, l-methyl -phenyl phos phinic acid, '1- ethyl-phenyl-phosphinic aeid (4), 1,3-dimethyl phei iy1- pass-paints 'acid (4), 1-isdpropyl phenyl phosphinic acid ('4) 1,2, l-trirnethyl phenyhphosphin'ic acid (5 'naphthylphospiiinicfacid 1), l-inethex -phenm phosphin'ic acid "(4), l ethoity phenyl phosphinic and (4) and the soluble salts thereof such as the ammonium, hydrazine, potassiii rnfsodium, zinc, a'n-ilino andthe like; aryl sulfihic acids such as phenyl-sulfinic 'ac'id, '4-chlor phenyl-s'ulfinic "did (1), 4-brom-phenyl-sulfinic acid (I), 4-io'dophenyl sulfinic acid (1), 3-nitro-phenyl-sulfinic acid (1), 4-nitrophenyl-sulfinic acid (1), l-methyl-phenyl-sulfinic acid (2), il methyl-phenyl-sulfinic acid (3), l-methyl-phenyl-sulfinic acid (4), 2-nitro-toluyl-sulfinic acid, 2,6 dinitro-t olu'ylsulfinic acid, '1,2 din-lethyhphenyhsulfinic acid 3), 1,2- dimethyl=phenyl=sulfinic 'acid (4), 1,3"-dimethylpheiiyls'ulfinic 'acid "(5'), 1;4=dimethyl phenyhsulfinic acid (2), ,1,2,4-trimethyl=phenyl sulfinic 'acid (5), l, 3, 5-trimethylphenyl-sulfinic "acid ('2') l=methyl 4=isopropyl=pheiiyl sulfinic acid'('2),naphthyl sulfinic acid (1), diphenyl sulfihjic acid ('4) anthracene sullinic 7 acid (2) 4'-methoiiy-l lrriethyl phenvl su'lfinic acid 3), 'S-riiethOXy-LS dimethybphenyl-sulfinic acid (2) and their soluble salts such "as amrnonium, sodium, potassium, barium, hydrazine, zinc, anilino and the like; and bore phosphoric "acid and its {soluble salts such asammonium, potassium, sodiiirh, hydrazino 'or the like.

As previously indicated, the dye brightening'agentiilay be added directly to the sensitizing solution, to .asuitable precoat or to a surface sizing operation in the paper mill. Generally, the quantity of the brighteningfag'ent used will range from .005 to 1% of the total weight of the-precoat, the sensitizing solution or the surface sizing agent. Larger quantities up to 1% are generally employed when the dye brightening agent isadded to the precoat or to the surface size.

The diazos and couplefs'employed are not critical to the invention. Thus, as the diazo, use may be made of the zinc chloride double salt of N,N-diethyla-mino-pbenzene :diazonium chloride, t or icadmium salt of the di a z o from N-liyd rok l-N niethyl-amino pamin'p setize'n from phenylamine; from flrnono-ethylairiinb-2 methylmino benzene; min l-N- ethyl-N h ydroxyethyl arriino3 methyl-4 amino benzene. Similarly, use 'may be made of means-5S describedin U.S. Patents 2,523,889, 2,298,444 andthe like.

various couplers suc'h'as tetrahydroxy biphenyl, 2,7-dihydroxy-naphthalene-3,6-disulfonic acid, the coupler of US. Patent 2,494,906, acetoacetanilide, 2,3-dihydroxynaphthalene-fi-sulfonic acid, resorcinol, l-hydroxy-naphthimidazole or the like.

The sensitizing composition may also contain the usual adjuncts such as stabililizing agents i.e., thiourea, thiosinamine, naphthalene trisulfonic acid; acids designed to retard precoupling such as citric acid, tartaric acid, boric acid, hygroscopic agents such as glycol, glycerin, dextrin or the like and metal salts for intensifying the image such as magnesium chloride, aluminum sulfate, nickel sulfate or the like.

The invention will be further illustrated by the following examples but it is to be understood that the invention is not restricted thereto.

Example I G. Water 60 Ethylene glycol 6 Isopropanol 1 Citric acid 3 Phenyl-phosphinic acid 1 Thiourea Magnesium chloride 3 Zinc chloride 3 2,3-dihydroxynaphthalene-6-sulfonic acid 4 p-Diazo-N,N-diethylaniline 2 Saponin 0.1 Water to--- 100 This solution was coated on an all sulfite diazotype paper, dried, and exposed under a mercury vapor lamp. Upon development over ammonia, a bright blue line resulted. The same formula without phenyl-phosphinic acid was duller and redder.

The above formula holds its color well in an acid atmosphere; the same formula minus phenyl-phosphinic acid gas fades badly to a brown color.

Example II G. Water 60 Ethylene glycol 3 Isopropanol 1 Citric acid 6 Phenyl-phosphinic acid 1 Thiourea 5 Magnesium chloride 3 Zinc chloride 3 2,3-dihydroxynaphthalene-6-sulfonic acid 1.5 Acetoacetanilide 0.15 Resorcinol 0.4 p-Diazo-N,N-diethylaniline 2 Saponin 0.1 Water to 100 This solution was coated on an all sulfite diazotype paper, dried, and exposed under a mercury vapor lamp. Upon development over ammonia, a neutral black resuited; the same formula without the aryl-phosphinic acid results in a much redder black line.

The above formula holds its color well in an acid atmosphere; without phenyl-phosphinic acid gas fading to a brown color takes place.

Zinc chloride 3 l-hydroxynaphthimidazole 2 p-N,N,-ethylbenzylamino benzene diazoniurn chloride 1.5 Saponin 0.1 Water to This solution was coated on an all sulfite diazotype paper, dried, and exposed under a mercury vapor lamp. Upon development over ammonia, a bright red line resuited; the same formula without phenyl-phosphinic acid would show decreased dye brightness.

The above precoat formulation was coated on an all sulfite diazotype paper and dried. When coated with red, black, or blue sensitizing formulas which do not contain phenyi-phosphinic acid, the favorable results ascribed to this acid are obtained because of its inclusion in the precoat formula.

Example V The procedure was the same as in Example I excepting that the phenyl-phosphinic acid was replaced by an equivalent quantity of phenyl-phosphonic acid.

Example VI The procedure was the same as in Example II excepting that the phenyl-phosphinic acid was replaced by an equivalent quantity of phenyl-sulfinic acid.

Example VII The procedure was the same as in Example IV excepting that the phenyl-phosphinic acid was replaced by an equivalent quantity of boro phosphoric acid.

Modifications of the invention will occur to persons skilled in the art. Thus, any of the print dye brightening agents may be used in lieu of those of the examples. We, therefore, do not intend to be limited in the patent granted except as necessitated by the appended claims.

We claim:

1. Light-sensitive diazotype material comprising a base having a light-sensitive diazo compound coated thereon, said light-sensitive diazo type material containing as a print dye brightening agent an organic acid selected from the class consisting of aryl phosphonic acids, aryl phosphinic acids, aryl sulfinic acids, boro phosphoric acid and the soluble salts thereof.

2. The product as defined in claim 1 wherein the print dye brightening agent is incorporated as a precoat.

3. The product as defined in claim 1 wherein the print dye brightening agent is incorporated in a size on the base.

4. The product as defined in claim 1 wherein the print dye brightening agent is imbibed to the base from the sensitizing solution.

5. The product as defined in claim 1 wherein the print dye brightening agent is phenyl-phosphinic acid.

6. Light-sensitive diazotype materials comprising a base having a light-sensitive diazo compound and a coupling component coated thereon, said light-sensitive diazotype material containing as a print dye brightening agent an organic acid selected from the class consisting of aryl phosphonic acids, aryl phosphinic acids, aryl sulfinic acids, boro phosphoric acid and the soluble salts thereof.

7. The product as defined in claim 6 wherein the print dye brightening agent is incorporated as a precoat.

8. The product as defined in claim 6 wherein the print dye brightening agent is incorporated in a size on the base.

print the 9. The product as defined in claim 6 wherein the dye brightening agent is imbibed to the base from sensitizing solution.

10. The product as defined in claim 6 wherein the print dye brightening agent is phenyl-phosphinic acid.

11. In the process of improving the dye brightness in prints obtained from light-sensitive diazotype materials by exposing said materials under a pattern and subjecting the exposed materials to development by means of an alkali in the presence of an azo dye coupling compound, the improvement which consists in effecting the development in the presence of an organic acid selected from the class consisting of aryl phosphonic acids, aryl phosphinic acids, aryl sulfinic acids, boro phosphoric acid and the soluble salts thereof.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Freedman et al.: The Preparation and Properties of Phosphonic Acids, Chemical Reviews, vol. 57, page 500. 

1. LIGHT-SENSITIVE DIAZOTYPE MATERIAL COMPRISING A BASE HAVING A LIGHT-SENSITIVE DIAZO COMPOUND COATED THEREON, SAID LIGHT-SENSITIVE DIAZO TYPE MATERIAL CONTAINING AS A PRINT DYE BRIGHTENING AGENT AN ORGANIC ACID SELECTED FROM THE CLASS CONSISTING OF ARYL PHOSPHONIC ACIDS, ARYL PHOSPHINIC ACIDS, ARYL SULFINIC ACIDS, BORO PHOSPHORIC ACID AND THE SOLUBLE SALTS THEREOF. 